Measurement of the adequacy of performance of Emergency Medical Technicians is still in a rather primitive state, in part because there is as yet little firm knowledge about what EMTs actually do. Most previous efforts at assessment have been directed toward performance capabilities of individuals, but it is clear that EMTs always work in teams and that it is team performance which must be evaluated. It seems unlikely that good measures of performance will be developed until there has been a chance to relate those measures to observations of EMTs under ordinary working conditions. The work proposed here involves the systematic observation of EMTs at different levels of experience and training and in both urban and rural locations. The observational protocol will involve both determination of adherence to mandated treatments and more implicit, global ratings of overall adequacy of performance. In addition the observers will be able to provide the first good data on various aspects of response time and performance times and patterns. Other measures such as supervisor ratings and paper-and-pencil tests will be employed with the EMTs measures for the much more expensive observational procedures. The work proposed here is directed toward rather basic measurement problems; consequently there will be a focus in the analysis on the psychometric properties of both observational and other measures, including traditional considerations of reliability and validity and detailed item analyses. Getting outcome measures for EMT performance is regarded as unusually challenging and maybe unlikely, but the possibilities will be explored during the course of this project.